Whisk 2 tablespoons oil, shallot, mustard, vinegar, thyme, salt, and pepper together in bowl; set aside.
Heat remaining oil in 12-inch nonstick skillet over medium heat until shimmering. Add green beans and 2 tablespoons water. Cover and cook, without stirring, until green beans are bright green and almost tender, about 5 minutes.
Uncover and continue to cook, stirring occasionally, until green beans are spotty brown, 3 to 4 minutes; transfer to serving platter. Whisk vinaigrette to recombine, then drizzle over green beans. Season with salt and pepper to taste. Serve.